The quantity of delegates obviously has to be high enough to prevent ease of collusion.  When Larimer was originally trying to change this number to 20 in Bitshares, I was like..wtf?  Are you serious?  20 people can collude easily.  Nearly everyone thought it was a horrible idea, but he was hell bent on making the system a "profitable DAC" over anything else.  It is best not to consider Bitshares a decentralized system, but the first bucket shop without a single point of failure.  Steem is essentially the same thing except a non-single point of failure Reddit hybrid.  It's not a decentralized currency or anything.  

There would need to be something like the original 101 delegate number or more to be considered remotely decentralized.  I'm not exactly a Vitalik fanboy or anything (obviously), but I think he considers this number needed to be around 1001.